I'm a little puzzled by this kind of question. Radio has been around for over a hundred years, and there have been countless thousands of radio books and magazines published.
You should start with a copy of the ARRL Handbook, and Bill Orr's Radio Handbook, and also the RSGB Handbook. Each one tackles the theory from slightly different points of view, so having more than one is a big help if you get stuck. New editions come out each year, but the older editions are just as useful. Most of the old editions can be found for free on-line.
Next are the many QRP books available, QRP Notebook 1&2 by Doug DeMaw, Solid state design for the radio amateur, W1fb's Design Notebook, and hundreds of others..
Then there are the thousands of Amateur Radio magazines which have been published.
For starters go to http://www.americanradiohistory.com/
Most of the magazines have published beginner's Tutorials over the years.